Colorado State University

About: Colorado State University is a education organization based out in Fort Collins, Colorado, United States. It is known for research contribution in the topics: Population & Laser. The organization has 31430 authors who have published 69040 publications receiving 2724463 citations. The organization is also known as: CSU & Colorado Agricultural College.

Solution-Based Synthesis and Characterization of Cu2ZnSnS4 Nanocrystals

Abstract: Recent advances have been made in thin-film solar cells using CdTe and CuIn1−xGaxSe2 (CIGS) nanoparticles, which have achieved impressive efficiencies. Despite these efficiencies, CdTe and CIGS are not amenable to large-scale production because of the cost and scarcity of Te, In, and Ga. Cu2ZnSnS4 (CZTS), however, is an emerging solar cell material that contains only earth-abundant elements and has a near-optimal direct band gap of 1.45−1.65 eV and a large absorption coefficient. Here we report the direct synthesis of CZTS nanocrystals using the hot-injection method. In-depth characterization indicated that pure stoichiometric CZTS nanocrystals with an average particle size of 12.8 ± 1.8 nm were formed. Optical measurements showed a band gap of 1.5 eV, which is optimal for a single-junction solar device.

Real‐time and retrospective forcing in the North American Land Data Assimilation System (NLDAS) project

Abstract: [1] The accuracy of forcing data greatly impacts the ability of land surface models (LSMs) to produce realistic simulations of land surface processes. With this in mind, the multi-institutional North American Land Data Assimilation System (NLDAS) project has produced retrospective (1996–2002) and real-time (1999–present) data sets to support its LSM modeling activities. Featuring 0.125° spatial resolution, hourly temporal resolution, nine primary forcing fields, and six secondary validation/model development fields, each data set is based on a backbone of Eta Data Assimilation System/Eta data and is supplemented with observation-based precipitation and radiation data. Hourly observation-based precipitation data are derived from a combination of daily National Center for Environmental Prediction Climate Prediction Center (CPC) gauge-based precipitation analyses and hourly National Weather Service Doppler radar-based (WSR-88D) precipitation analyses, wherein the hourly radar-based analyses are used to temporally disaggregate the daily CPC analyses. NLDAS observation-based shortwave values are derived from Geostationary Operational Environmental Satellite radiation data processed at the University of Maryland and at the National Environmental Satellite Data and Information Service. Extensive quality control and validation efforts have been conducted on the NLDAS forcing data sets, and favorable comparisons have taken place with Oklahoma Mesonet, Atmospheric Radiation Measurement Program/cloud and radiation test bed, and Surface Radiation observation data. The real-time forcing data set is constantly evolving to make use of the latest advances in forcing-related data sets, and all of the real-time and retrospective data are available online at http://ldas.gsfc.nasa.gov for visualization and downloading in both full and subset forms.

Partitioning Species Diversity across Landscapes and Regions: A Hierarchical Analysis of α, β, and γ Diversity

Abstract: Species diversity may be additively partitioned within and among samples (alpha and beta diversity) from hierarchically scaled studies to assess the proportion of the total diversity (gamma) found in different habitats, landscapes, or regions. We developed a statistical approach for testing null hypotheses that observed partitions of species richness or diversity indices differed from those expected by chance, and we illustrate these tests using data from a hierarchical study of forest-canopy beetles. Two null hypotheses were implemented using individual- and sample-based randomization tests to generate null distributions for alpha and beta components of diversity at multiple sampling scales. The two tests differed in their null distributions and power to detect statistically significant diversity components. Individual-based randomization was more powerful at all hierarchical levels and was sensitive to departures between observed and null partitions due to intraspecific aggregation of individuals. Sample-based randomization had less power but still may be useful for determining whether different habitats show a higher degree of differentiation in species diversity compared with random samples from the landscape. Null hypothesis tests provide a basis for inferences on partitions of species richness or diversity indices at multiple sampling levels, thereby increasing our understanding of how alpha and beta diversity change across spatial scales.

Re-embedding global agriculture: The international organic and fair trade movements

Abstract: The international organic agricultureand fair trade movements represent importantchallenges to the ecologically and sociallydestructive relations that characterize the globalagro-food system. Both movements critique conventionalagricultural production and consumption patterns andseek to create a more sustainable world agro-foodsystem. The international organic movement focuses onre-embedding crop and livestock production in ``naturalprocesses,'' encouraging trade in agriculturalcommodities produced under certified organicconditions and processed goods derived from thesecommodities. For its part, the fair trade movementfosters the re-embedding of international commodityproduction and distribution in ``equitable socialrelations,'' developing a more stable and advantageoussystem of trade for agricultural and non-agriculturalgoods produced under favorable social andenvironmental conditions. The international market forboth organic and fair trade products has grownimpressively in recent years. Yet the success of thesemovements is perhaps better judged by their ability tochallenge the abstract capitalist relations that fuelexploitation in the global agro-food system. While theorganic movement currently goes further in revealingthe ecological conditions of production and the fairtrade movement goes further in revealing the socialconditions of production, there are signs that the twomovements are forging a common ground in definingminimum social and environmental requirements. I arguefrom a theoretical and empirical basis that what makesfair trade a more effective oppositional movement isits focus on the relations of agro-food trade anddistribution. By demystifying global relations ofexchange and challenging market competitiveness basedsolely on price, the fair trade movement creates aprogressive opening for bridging the wideningNorth/South divide and for wresting control of theagro-food system away from oligopolistic transnationalcorporations infamous for their socially andenvironmentally destructive business practices.